1. Field of the Invention
This invention relates generally to an optical architecture for directing a laser beam and, more particularly, to an optical architecture for directing a collimated high-energy laser beam through an aperture stop at a desired angle in one or two dimensions using a single tilt mirror.
2. Discussion of the Related Art
High-energy lasers (HEL) have various applications in the art, such as target range finding and destruction. FIG. 1 is a general plan view of a laser system 10 including a high-energy laser 12 that emits a collimated laser beam. The laser beam is received by an optical architecture 14 that provides beam conditioning and directivity to cause the beam to be emitted through an aperture stop 18 having an aperture 20 at a desired angle towards a target (not shown). Because the beam is high energy, it is typically undesirable to re-image the beam, i.e., bring it to a focus, within the optical architecture 14 because the focused beam causes air to break down, and other adverse effects, which prevents the optical architecture 14 from operating properly in a manner that is well understood in the art.
One solution to this problem is to provide a vacuum chamber in the optical architecture 14 at the location where the beam needs to be focused so that the beam does not interact with air. However, such vacuum chambers for this application are typically large, heavy, complex and costly.
Another solution to this problem is to maintain the laser beam collimated as it propagates through the optical architecture 14. Current optical architectures for providing beam direction control that maintain the beam collimated employ two tilt mirrors. Essentially, one of the tilt mirrors applies the desired beam angle, but translates the beam, and the other tilt mirror directs the tilted and translated beam to the center of the aperture 20. However, the algorithms required to tilt two mirrors accurately and properly in concert with each other are difficult to implement and are typically unreliable. It would be desirable to simplify the optical architecture 14 by eliminating one of the tilt mirrors to reduce the complexity, size, weight, cost and power consumption of the optical architecture 14.